Tissue concentrations of antibiotics given prophylactically during colorectal cancer surgery.

Background/aims: This study was designed to clarify the pharmacokinetics of prophylactically administered cefmetazole in serum, intestinal tissue, and subcutaneous adipose tissue in patients who underwent surgery for colorectal cancer.
Methodology: Cefmetazole sodium (1 g) was given intravenously during the induction of anesthesia, followed by a 1-g dose after 3 hours. Blood samples were taken at the start of surgery, immediately before administration of the additional dose of cefmetazole, at the time of lesion resection, and at the time of wound closure. Tissue samples were obtained immediately after lesion resection and at the time of wound closure. Concentrations of cefmetazole in serum and tissue were measured by high performance liquid chromatography using an internal standard for calibration. Minimum inhibitory concentrations (MIC80) of cefmetazole for Escherichia coli, Klebsiella pneumoniae, and Bacteroides fragilis were measured, and pharmacokinetics were evaluated.
Results: In subcutaneous adipose tissue, cefmetazole concentrations were maintained higher than the MIC80's for E. coli and K. pneumoniae, but were low in all patients regardless of the time of measurement.
Conclusions: The low transition rate of cefmetazole into subcutaneous adipose tissue indicates the need for additional measures, such as high-pressure washing of the subcutaneous wound tissue.